Axial gap electric motor-driven pump



Patented Apr. 21, 1953 AXIAL GAP ELECTRIC MOTOR-DRIVEN PUM John B.Cataldo, Annandale, N. J., assignor, by

mesne assignments, to John B. Pierce Foundation, New York, N. Y., acorporation of New York Application January 19, 1948, Serial No. 3,042

(Cl. 10S- 87) 2 Claims.

This invention relates to pumps and more particularly t pump and motorcombinations in which there are no external shafts requiring packingglands or leakproof bearings.

Heretofore pump and motor combinations have been proposed but in most ofthese the drive shaft from the motor requires at least one packing glandor leakproof bearing where it passes into the pump housing. In manyinstallations such a packing gland or bearing is unobjectionable andsatisfactory but such glands or bearings soon deteriorate and leak ininstallations where high temperature fluids or iuids which chemicallyreact with the packing oi the gland or with the bearing material arebeing pumped.

It is accordingly an object of the present invention to provide a novelpump and motor combination in which no packing glands or leakproofbearings are required.

Another object is to provide such a combination in which there are noexternal'shafts requiring leakproof bearings or glands.

Another object is to provide such a combination which is assembled in aunitary housing.

Another object is to provide such a combination in which the motor is anaxial air gap electric motor driving a pump through a shaft having noexternal bearings or glands.

Another object is to provide such a combination in which the stator ofthe axial air gap motor is protected from the fluid being pumped by anonmagnetic partition interposed between the stator and the rotor.

Another object is to provide such a combination which is compact,simple, eiiicient and relatively cheap and easy to assemble- The pumpand motor combination of my invention is capable of many mechanicalembodiments and is capable of use with many of the high temperature heattransfer materials, including the tetra-aryl ortho silicates, and withfluids which will have a deteriorating action upon conventional packingmaterials and upon conventional leakprooi bearings. One embodiment of myinvention is shown in the accompanying drawing to illustrate the sameand will be described hereinafter as used for pumping tetra-aryl orthosilicates. This embodiment and the description thereof should in no waybe construed as defining or limiting my invention and reference shouldbe had to the appended claims for this purpose.

The tetra-aryl ortho silicates are heat transfer compounds described inthe Johnston Patent No. 2,335,012 dated November 23, 1943. Thesecompounds have an approximate range of use from F. to 700 F. and withinthis range are an eflicient heat transfer medium. It has been found thatat high temperatures the tetra-aryl ortho silicates will in time causedeterioration of known packing materials with resulting leaks at glandsand bearings. Such leaks are highly undesirable because, among otherthings, of the waste of the tetra-aryl ortho silicate.

Referring particularly to the drawing, an embodiment of my combinationpump and motor is there shown in which the housing of the pump and motoris formed in three sections I0, l I and I2. Section I0 encloses thestator of the axial air gap type electric motor having suitable polepieces I3 for the stator formed integrally therewith. Pole pieces I3 maysupport any suitable type of windings I4 to provide the magnetic uxrequired. Section i0 includes an outwardly extending rim I5 which issuitably apertured at I6 to receive bolts Il which secure section I0 tohousing section ii.

Housing section IIJ is internally and circumferentially grooved at I8 toreceive a diaphragm I9.

iaphragm I9 is of a suitable nonmagnetic material such as mica or one ofthe synthetic resins resistant to high temperatures and to deteriorationby the fluid being pumped. Groove I8 and diaphragm I9 are so tted as toform a duid-tight seal when housing sections I0 and Il are boltedtogether, section II having an annular shoulder 20 which bears upondiaphragm I9 and forces diaphragm I9 into groove I8. Diaphragm i9 may beof any suitable thickness. Since it is desirable to reduce the gapbetween the stator and the rotor to a minimum diaphragm I9 may berecessed at 2i to receive pole pieces I3 leaving a thin section ofdiaphragm I9 over each pole piece I3.

Housing section Ii contains the rotor 22 of the motor. Rotor 22 includespole pieces 23 which may carry suitable windings 24 of the non-insulatedtype conventional in induction motors. Pole pieces 23 project towarddiaphragm I9 with a minimum clearance therebetween. Rotor 23 is mountedupon and is suitably secured to a shaft 25 which is mounted for rotationin a suitable bearing 2B carried by bearing support 2l formed in sectionI I. A partition 28 is connected to bearing support 2? adjacent rotor 22and forms a chamber with housing II for rotor Z2. A partition 2S isconnected to the other end of bearing support 2l and also forms a partof the pump housing including a part of the valute casing 3D and part 3|of the discharge port. Partition 29 is cut away at 32 to give suitableclearance between pump impeller 33 and partition 29.

Impeller 33 is mounted for rotation on shaft 25 and is suitably securedthereto as by key 34 and nut 35. Section i l is provided with anoutwardly extending rim 36 which is apertured at 31 to receive bolts 38to secure housing section Il to housing section l2,section l2 beingprovided with a cooperating rim 39 -apertured and internally threaded atl0 to receive bolts 38. Housing section l2 forms a chamber for impeller33 and is provided with a flanged uid inlet 4i and a flanged portion l2cooperating with part 3l to form' the fluid discharge port. The abuttingfaces of housing sections itl, Il and 12V-are nicely machined to securedfluid-tight joints when bolts I7 and 38 are tightened. When desirablegasketsV maybe placed between these surfaces to assure such joints. Y

With the pump and motor combination fmy invention organized as abovedescribed when it is desired to use the same for circulating tetraarylortho silicate at high temperaturesin a system employing such tetra-arylortho silicate iianged inlet Il! is connected into the system at anysuitable point and discharge port 3I- l2 is also connected into thesystem. Electric energy is then supplied to windings i4 and rotor 22 isrotated thus rotating shaft Y25 and iinpeller 33. Rotation of impeller33 draws the tetra-aryl ortho silicate into housing section I2 Vandexpels it by centriiugalaction into volute casing 3|] and out of thedischarge port 3i-42. Some of the tetraaryl ortho silicate may' fromtime to time work through bearing 26 and into the rotor. chamber inhousing section il but` tetra-aryl ortho silicate in this chamber is notobjectionable since it can have no effect on the non-insulated windings26 and may give a certain amount of lubricating effect, These silicateshave no eiect Yon the noninsulated windings 25 because they do notattack the metals of the windings. The tetra-aryl ortho silicate whichiinds its way into the rotor chamber is blocked by diaphragm i9fromentering the stator chamber and therefore can do no damage to thestator windings.

It will now be apparent that by the present invention i have provided anovel pump and motor combination in which no packing glands or leakproofbearings are required; `in which there are no external shafts requiringpacking glands or leakproof bearings; in which the combination ismounted in a unitary housing; in which an axial type air gap electricmotor drives the pump through a shaft having no external bearings orglands; in which the stator of the motor is protected from the iiuidbeing pumped; and which is compact, simple, efficient and relativelycheap and easy to assemble.

Changes to or modifications of the illustrative embodiment of myinvention may now be suggested to those skilled in the art withoutdeparting from my inventive concept and reference should be had to theappended claims to determine thescope of this invention.

What isV claimed is:

l. In a pump as described, a housing comprising, two axiallyalignedportions, an axial air gap electric motor mounted in said housing,including ank axially spaced stator and rotor, a nonmagnetic diaphragm,between said stator and said rotor and forming a iiuid tight compartmentwith the rst portion of said housing and enclosing said stator, a shaftoperatively connected to said rotor, an impeller mounted on said shaft,said shaft, rotor, and-impeller being enclosed by the second portion ofsaid housing, a bearing in which said-shaft is journaled, said bearingbeing supported by the second portion of the housing and disposedbetween said rotor and said impeller, the housing being provided with Yauid inlet port and a iluid discharge port adjacent said impeller and incommunication therewith.

2. In a pump as described, a housing formed of at least three partsjoined in axial alignment iniluid-tight relation, an axial air gapelectric motor including a stator disposed in one of said parts, and arotor disposed in the next adjacent part, a nonmagnetic diaphragmsecured in a fluid-tight seal between said one par and the said nextadjacentfpart and .disposed opposite and proximate to said stator, abearing in said second named part, a shaft rotatably mounted in saidbearing and extending into the third housing part and having said rotormounted thereon opposite and proximate to said diaphragm and a pumpimpeller mounted on said shaft in said third` part.

JOHN B. CATALDO.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 592,244 Fay Oct. 25, 1897 1,119,648 Sheldon Dec. l, 19142,245,577 Dieckman une 17, 1941 2,592,752 Shenstone Apr. l5, 1952

